[London] Coca-Cola GB is giving away more than 4 million cans of Diet Coke in the U.K. this week and increasing the brand's U.K. marketing spending by 50% in 2005. The giveaway highlights the new "sugar-free" label appearing on cans and in ads in response to research findings in both the U.K. and the U.S. that many consumers don't understand diet colas are calorie-free. According to Julia Goldin, marketing director for Coca-Cola GB, the U.K. is Diet Coke's most successful market. Diet Coke sales passed those of regular Coke last year for the first time, compared to the U.S., where Diet Coke is the third-most-successful cola brand with a 9% share of volume, after Coke Classic and Pepsi Cola with 19% and 13% respectively. New ads by VCCP, London, with the tagline "For those who love life" feature an active tortoise called "Tort" who skateboards and plays soccer. With 40% of Diet Coke consumed by men in the U.K., ads are aimed at both men and women.